Team News:Donncha O'Callaghan joins Donnacha Ryan in the second row for Munster's trip to Scarlets on Saturday as one of eight changes to the side that beat Ospreys last weekend.

There are four changes in the backs with Duncan Williams taking the place of Cathal Sheridan at scrum half after the Sligo man broke a bone in his forearm last week, with Ian Keatley remaining at out-half.

The IRFU and Munster Rugby have announced today that Williams has signed a one-year contract extension that will see him stay with the province until June 2015.

The Academy graduate moved on to a full contract at the start of the 2010/11 season and the 27-year-old has since made steady progression, providing invaluable experience in a key position.

Johne Murphy and Gerhard van den Heever are both drafted into the side on the wings with Simon Zebo moving to full-back.

Denis Hurley comes in at inside centre with Casey Laulala keeping his place outside him.

Two of the four changes in the forwards involve the front row with Ireland international props David Kilcoyne and Stephen Archer linking up with hooker Duncan Casey who will be making his fifth start for the province.

O'Callaghan and Ryan make up the second row pairing and CJ Stander takes over from Sean Dougall in the back row alongside Tommy O'Donnell and James Coughlan who captains Munster once again from number 8.

Young Munster clubman Ger Slattery, James Cronin and BJ Botha provide front row cover on the bench, while fellow forwards David Foley and Dougall will also be keen to make an impact off the bench.

Reserve backs Gerry Hurley, who captained the Ireland Club team to two recent wins, JJ Hanrahan and Ronan O'Mahony complete the matchday 23.

Munster face the Scarlets in Llanelli on Saturday at 6.30pm. The game will be televised live on RTÉ Two and S4C with live updates here.

Meanwhile, Scarlets boss Simon Easterby has made only one change to the side that secured a 25-21 victory over Edinburgh last Saturday afternoon.

The Welsh region welcome the return of co-captain and Wales and British & Irish Lions centre Jonathan Davies.

Davies will line up alongside former England international Olly Barkley in a new-look centre partnership for the Scarlets as the home side look to make it three league wins on the trot.

Pre-Match Quotes:Rob Penney (Munster) - "It (a clean sweep over the Welsh regions) would be an amazing achievement. But it will all come down to how the boys prepare and with the short turnaround and two away trips, it's a difficult week for us.

"You would always be pleased when you’re not letting too many tries through - it is working well for us (with 39 scored and 15 against in the league so far).

"It is a key plank of any team because it means you don’t have to score too many tries yourself. It (the tries for and against ratio) could be indicative of anything, but we're pretty proud of it.

"The Scarlets bring an intense passion to the forward exchanges. They are just ruthless and we are going to have to deal with that.

"They have some quality in their backs so they are not a team you would go to and just turn up and play and say you’re going to be okay. We have got to be in really good shape mentally as well as physically."

Simon Easterby (Scarlets) - "Munster are a pretty good outfit at the minute and are pretty settled. They are still able to pick a very strong team despite missing a number of internationals.

"We are under no illusion that they'll be coming here nothing less than well equipped to mix up their game and we will have to be at our best and far better defensively.

"Having narrowly missed out on a victory late on in injury-time against Munster at Musgrave Park before Christmas we've had plenty of motivation in training this week

"We put ourselves in a really good position to win away from home but gave them a foothold in the dying minutes and managed to stick at it.

"We had a clear vision coming back into this block of RaboDirect PRO12 fixtures, there were 50 points up for grabs and we're focused on being as clinical as we can be to pick up as many of those 50 points as we can.

"We just need to keep believing and keep pushing. I definitely feel that we can take confidence from the last couple of results and take on Munster with plenty to look forward to in the coming weeks."

- The Scarlets have won their last two matches in the RaboDirect PRO12, in Treviso and at home to Edinburgh, but have not won three in-a-row in the league since last April

- The Welshmen have won three of their last four fixtures with Irish provinces at Parc y Scarlets

- Munster's single defeat in the PRO12 since round 3 was 29-19 against Ulster at Ravenhill on January 3

- The Munstermen are going for a clean sweep of eight successive wins over Welsh regions this season, a feat that has never been accomplished by any side before

- The Scarlets' 18-10 victory over Munster at Parc y Scarlets in February 2013 ended an impressive run of success for Munster in matches played in Llanelli (the home side never having won on their own patch since March 2007)